added description

README.rst

@@ -22,9 +22,17 @@ dipper
     :alt: Join the chat at https://gitter.im/bird-house/birdhouse
 
 dipper (the bird)
-  *dipper is a bird ...*
+  *Dipper is a stout little bird that thrives in fast-flowing rivers.*
 
-A Web Processing Service for Climate Data Analysis of Flood risks.
+This namesake Web Processing Service produces data files and maps on flood warning level forecasts in Europe on a seasonal scale.
+
+Warning levels are produced for sub-basins that has an average area of 250km2 and are presented with a weekly resolution.
+
+The warning levels are determined from a historical simulations for the past 30 years and applied on a 31 week seasonal forecast at the start of each month.
+
+The color, if any, shows the level of the first occuring warning whithin the forecast period.
+Note that a higher warning level occuring in a specifig sub-basin can be obscured by a lower level occuring closer in time, use the functionality to choose levels to explore this.
+Color intensity is lower the later the warning occurs in the forecast period. This means that a clear vibrant color is close in time and a faded color is distant in time up to the maximum of forecast week 30 which is then barely visible.
 
 Documentation
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